1 2 DYNAMI CS OF THE DI SPLACEMENTS BY VI BRATI ONS ON PLANE SI EVES Liviu BRÎNDEU 1 , Radu ILEA 2 1 Politehnica University of Timisoara, e-mail: brindeu@mec.utt.ro 2 Banat Agricultural University of Timisoara, e-mail: ilearn@k.ro Abstract: The separation operation of different materials at a large range of machines is effected thanks to the vibration of the working element. The separation operation is analyzed with the help of the model of particle what executes displacements by vibrations on a rough plane. Displacement regimes of the particle are studied, by forward and backsliding and by detachment. Because of the velocity discontinuity what appears as a result of the friction between the particle and plane or of the fall on the plane in the case of detachment, vibro-impacting motion regimes appear. In consequence, for the motion study, the well-known methods are applied, concerning the study of vibro-impacting regimes. The obtained results are in concordance with the experimental data, obtained on the machines what generate displacements by vibrations. At each machine, series of measurements were performed, in different points and different working conditions. Keywords: motion, plane sieves, sliding regimes, vibrations 1. INTRODUCTION The dynamic study of the separation processes, effected by the material displacement, in the presence of friction on the surfaces of plane sieves, is developed on the basis of the two mass model in contact with friction [1] - [3]. It must underline that in a lot of processes, based on vibrational displacements, can also appear, motions with detachments and falls of the particle on the vibrating plane. This kind of regimes are vibro-impacting phenomena and form an up-to-date field [4] - [5]. Initially, only vibrational displacements with sliding on the vibrating plane are taken into account; these ones have vibro-impacting character, because of the discontinuity of the friction force. In a series of anterior papers [6] - [7], new models and study methods were conceived for the determination of motion regimes with impacts and important